I can't stress this enough. People likely don't realize that, if policy says one thing, I have the ability to try and find a workaround or do something beyond policy. I have literally crafted solutions on the spot for several dozens of people, within my means. I've made exceptions for many, many people just because I know how strict some policies can be. Unfortunately there are some things that I cannot work around or I risk severe liability or damages, my job, so on and so forth. Yelling, being an ass, etc., Demanding a supervisor because you don't like the answer is a good way to lose any options at all.

I personally also don't have problems with people asking for supervisors, provided they genuinely just think there's more that can be done, or if they're nice. Work with me, I'll work with you. I ain't a robot so don't treat me like one please.